&EPA
United States
Environmental Protection
Agency
Great Lakes
National Program Office
77 West Jackson Boulevard
Chicago, Illinois 60604
EPA 905-R-93-001
FEBRUARY 1993
Assessment and Remediation
Of Contaminated Sediments
(ARCS) Program
BASELINE HUMAN HEALTH
RISKS RESULTING FROM
PCB CONTAMINATION AT THE
SHEBOYGAN RIVER, WISCONSIN,
AREA OF CONCERN
United States Areas of Concern
ARCS Priority Areas of Concern
PRIHTKD OH UCTCLED PAPER*
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o,
BASELINE ASSESSMENT OF HUMAN HEALTH RISKS
RESULTING FROM PCB CONTAMINATION AT THE
SHEBOYGAN RIVER, WISCONSIN, AREA OF CONCERN
by
JUDY L. CRANE
AScI CORPORATION
ATHENS, GA 30605
PROJECT OFFICER
ROBERT B. AMBROSE, JR.
ENVIRONMENTAL RESEARCH LABORATORY
ATHENS, GEORGIA 30613
ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
ATHENS, GEORGIA 30613
U.S. Environmental Protection Agency
GLNPO Library Collection (PL-12J) ^
77 West Jackson Boulevard,
Chicago, IL 60604-3590
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DISCLAIMER
The information in this document has been funded wholly or in part by the
United States Environmental Protection Agency under Contract Number 68-C1-0012
to AScI Corporation. It has been subject to the Agency's peer and administrative
review, and it has been approved for publication as an EPA document. Mention of
trade names or commercial products does not constitute endorsement or
recommendation for use by the U.S. Environmental Protection Agency.
n
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PREFACE
This risk assessment was prepared as part of the Assessment and Remediation
of Contaminated Sediments (ARCS) program coordinated by the U.S. EPA Great
Lakes National Program Office. The work by AScI Corporation was completed under
contract no. 68-C1-0012 with the U.S. EPA Environmental Research Laboratory-
Athens by Judy L. Crane, Ph.D. under the supervision of James L. Martin, Ph.D., P.E.,
AScI Site Manager. This work was performed through the U.S. EPA Center for
Exposure Assessment Modeling, Mr. Robert Ambrose, Jr., P.E., Manager.
iii
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FOREWORD
Risk assessment has been defined as the characterization of the probability
of adverse effects from human and ecological exposures to environmental hazards.
Risk assessments are quantitative, chemical-oriented characterizations that can
use statistical and biological models to calculate numerical estimates of risk to
human health or the environment. The concept of risk assessment is a
cornerstone on which the U.S. Environmental Protection Agency builds programs
to confront pollution problems in air, water, and soil under the direction of
Congressional mandates. One such mandate is the Clean Water Act, which
includes a directive to the Agency to study the control and removal of toxic
pollutants in the Great Lakes, with emphasis on removal of contaminants from
bottom sediments. Charged with performing this study is EPA's Great Lakes
National Program Office (GLNPO) located in Chicago, IL. GLNPO administers
the Assessment and Remediation of Contaminated Sediments (ARCS) program to
examine the problem of contaminated sediments using a multidisciplinary
approach involving engineering, chemistry, toxicology, modeling, and risk
assessment.
In support of the GLNPO, the Environmental Research Laboratory-Athens
began a series of studies under the ARCS program that will culminate in a
baseline risk assessment for each of five Great Lakes Areas of Concern (AOQ--
Buffalo River, NY, Grand Calumet River/Indiana Harbor Canal, IN, Saginaw
River, MI, Ashtabula River, OH, and Sheboygan River, WI. This report describes
a baseline human health risk assessment for the population within the Grand
Calumet River/Indiana Harbor Canal AOC. The assessment, which is based on
available environmental data, is designed to provide a conservative estimate of
carcinogenic and noncarcinogenic risks to human health under the baseline, no-
action alternative.
Rosemarie C. Russo, Ph.D.
Director
Environmental Research Laboratory
Athens, Georgia
IV
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ABSTRACT
The Assessment and Remediation of Contaminated Sediments (ARCS)
program, a 5-year study and demonstration project relating to the control and
removal of contaminated sediments from the Great Lakes, is being coordinated and
conducted by the U.S. Environmental Protection Agency's (EPA) Great Lakes
National Program Office (GLNPO). As part of the ARCS program, baseline human
health risk assessments are being performed at five Areas of Concern (AOCs) in the
Great Lakes region. The Sheboygan River, located in eastern Wisconsin, is one of
these AOCs.
In this report, exposure and risk assessment guidelines, developed for the EPA
Superfund program, have been applied to determine the baseline human health risks
associated with direct and indirect exposures to sediment-derived contaminants in the
Sheboygan River AOC. These risks were estimated for carcinogenic effects (i.e.,
probability of an individual developing cancer over a lifetime).
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TABLE OF CONTENTS
DISCLAIMER ii
PREFACE iii
FOREWORD iv
ABSTRACT v
LIST OF FIGURES vii
LIST OF TABLES vii
ACKNOWLEDGMENTS viii
INTRODUCTION 1
EXPOSURE ASSESSMENT 3
Exposure Pathways 3
Chemical Intakes 3
Exposure Through Fish Consumption 4
Exposure Through Dermal Contact with Floodplain Soils 6
RISK ASSESSMENT 9
UNCERTAINTIES 11
CONCLUSIONS 15
REFERENCES 17
VI
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LIST OF FIGURES
Figure
1 Sheboygan River AOC boundaries . . .
LIST OF TABLES
Table Page
1 Generic Equation for Calculating Chemical Intakes (USEPA,
1989a) 4
2 Mean PCB Concentrations in Four Species of Fish Collected
from the Sheboygan River 6
3 Equation Used to Estimate Contaminant Intakes Due to
Ingestion of Fish 7
4 Parameters Used in Estimating Contaminant Intakes Due to
Ingestion of Fish from the Sheboygan River 8
5 Equation used in Estimating the Absorbed Dose of PCBs due
to Dermal Contact with Floodplain Soils 9
6 Parameter Values Used in Estimating the Absorbed Dose
Due to Dermal Contact with Floodplain Soil (Numbers
in Parentheses Correspond to Reasonable Maximum
Exposures) 10
7 Carcinogenic Risk from Consuming Sheboygan River Fish,
Typical Exposure, FI = 0.05 12
8 Carcinogenic Risk from Consuming Sheboygan River Fish,
Reasonable Maximum Exposure, FI = 0.1 13
9 Carcinogenic Risk from Consuming Sheboygan River Fish,
Subsistence Exposure, FI = 0.2 14
10 Estimated Carcinogenic Risk Due to Dermal Exposure to
Contaminated Floodplain Soils, Typical Exposure
Scenario 16
11 Estimated Carcinogenic Risk Due to Dermal Exposure to
Contaminated Floodplain Soils, Reasonable Maximum
Exposure Scenario 16
VII
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ACKNOWLEDGMENTS
This risk assessment was performed in cooperation with Bonnie Eleder,
Remedial Project Manager for the Sheboygan River/Harbor Superfund site, of the
Office of Superfund, U.S. EPA Region V. Helpful information about the Hmong
population in Sheboygan was obtained from Kim Bro (Wisconsin Department of
Health and Social Services) and Jim Amrhein (Wisconsin Department of Natural
Resurces). This document was reviewed by the ARCS Risk Assessment and
Modeling Work Group and by the U.S. EPA Environmental Research Laboratory-
Athens.
Vlll
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INTRODUCTION
The Assessment and Remediation of Contaminated Sediments (ARCS)
program, a 5-year study and demonstration project relating to the control and
removal of contaminated sediments from the Great Lakes, is being coordinated and
conducted by the U.S. Environmental Protection Agency's (EPA) Great Lakes
National Program Office (GLNPO). As part of the ARCS program, baseline human
health risk assessments are being performed at five Areas of Concern (AOCs):
Ashtabula River, OH; Buffalo River, NY; Grand Calumet River/Indiana Harbor
Canal, IN; Saginaw River, MI; Sheboygan River, WI. This risk assessment will focus
on the baseline human health risks resulting from exposure to sediment-derived
contaminants at the Sheboygan River.
The Sheboygan River/Harbor AOC includes approximately 22.5 km of the
Sheboygan River and the entire Sheboygan Harbor (47.5 hectare) (Figure 1). This
area was designated as a Superfund site in 1985 due to widespread contamination of
the sediments and fish by PCBs. In addition, the sediments have been contaminated
with several heavy metals (e.g., cadmium, chromium, lead, mercury, nickel, and
zinc). Due to the level of PCB contamination in the fish, a "do not eat" fish advisory
has been issued by the Wisconsin Department of Natural Resources (DNR) and the
Wisconsin Division of Health for all resident fish species, including smallmouth bass,
walleye, and panfish as well as for migratory species such as chinook salmon and
steelhead trout. Despite these fish advisories, some people continue to consume fish
from the Sheboygan River and Harbor.
The extent of contamination at the AOC has been described in detail in the
Remedial Investigation/Enhanced Screening (RI/ES) report for the Sheboygan River
and Harbor (Blasland and Bouck Engineers, 1990). A human health endangerment
assessment, conducted as part of the RI/ES report, indicated that three long-term
exposure scenarios resulted in "unacceptable" carcinogenic risks (i.e., cancer risks
greater than the 1CT4 to 10"7 range):
• Dermal exposure to river sediments containing the maximum observed
PCB concentrations
• Ingestion of certain fish species that contained PCB concentrations
greater than the FDA limit (i.e., 2.0 mg/kg)
• Ingestion of certain waterfowl species contained PCB concentrations
greater than 4 mg/kg in edible portions
The most highly contaminated sediments in the Sheboygan River were
dredged between 1989 and 1991 under two phases. Under the first phase, dredged
sediments were placed in a Pilot Confined Treatment Facility (CTF) (Eleder, 1991); the
CTF is being used to study the effectiveness of enhanced natural biodegradation for
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/
-N
1 Miles
Incorporated Am (2J
Communily Center •
Dam '
River Ua«n boundary ——
Walerlhed boundary — -
Coumr boundary ——
Figure 1. Sheboygan River AOC boundaries.
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treatment of PCBs. The second phase was implemented under a Removal Action;
these sediments have been stored temporarily in a tank until a decision can be made
in the Record of Decision as to their final disposal. In addition, less contaminated
sediments have been armored in place. A monitoring program has been designed
and implemented to assess the effectiveness of the removal, armoring, and
biodegradation of sediments. A fish monitoring program was begun in 1989 and
continues today. As part of the monitoring program, data were collected during 1991
to determine total PCB levels in floodplain soils and in four species of fish.
Rather than duplicate the effort of the RI/ES endangerment assessment, this
baseline risk assessment for the ARCS program sought to update the endangerment
assessment with new data. Exposure and risk assessment guidelines, developed for
the EPA Superfund program, were used to estimate the carcinogenic risk from
exposure to sediment-derived contaminants (i.e., PCBs).
EXPOSURE ASSESSMENT
Exposure Pathways
Residents of Sheboygan and the surrounding area may be exposed to
sediment-derived contaminants through two complete exposure pathways: 1)
consumption of contaminated fish (e.g, river steelhead, chinook salmon, smallmouth
bass, and river carp) and 2) dermal exposure to floodplain soils. These pathways
were selected because recent data were available and because other exposure
pathways had previously been evaluated for the RI/ES endangerment assessment.
There was no evidence that children would be ingesting floodplain soils (i.e., pica
behavior) in the AOC; thus, this exposure scenario was not determined to be
complete. People may inadvertently ingest some dust from the soil if they do not
wash their hands before eating. However, much more soil is dermally contacted than
is ingested during normal exposure scenarios, and dermal contact usually poses a
greater threat than soil ingestion. Thus, the ingestion of dust from the hands was not
evaluated here.
Chemical Intakes
The intake of PCBs into the body was determined by normalizing the
exposures for time and body weight. The general equation for calculating chemical
intake is given in Table 1. Several variables were used to determine intake based on
specific information about the exposed population and the period over which the
exposure was averaged. Using EPA Superfund guidance, typical (i.e., average)
exposures were assumed to occur over a period of 9 years; reasonable maximum (i.e.,
the maximum exposure that is reasonably expected to occur at a site) and subsistence
exposures were assumed to occur over a period of 30 years (USEPA, 1989a). The
subsistence pathway only applied to a subpopulation of anglers and their families.
The exposure durations were extrapolated over a period of 70 years for estimating
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TABLE 1. GENERIC EQUATION FOR CALCULATING CHEMICAL INTAKES
(USEPA, 1989a)
J =
C X CR X EFD
BW X AT
where:
I
CR
EFD
BW
AT
Intake = the amount of chemical at the exchange boundary (mg/kg body weight-day)
Chemical-Related Variables
Chemical Concentration = the average concentration contacted over the exposure
period (e.g., mg/L)
Variables that Describe the Exposed Population
Contact Rate = the amount of contaminated medium contacted per unit time or
event (e.g., L/day)
Exposure Frequency and Duration = how long and how often exposure occurs.
Often calculated using two terms, EPED, where
EF = exposure frequency (days/year)
ED = exposure duration (years)
Body Weight = the average body weight over the exposure period (kg)
Assessment-Determined Variables
Averaging Time = period over which exposure is averaged (days)
carcinogenic risks. Exposures were added across pathways (i.e., consumption of fish
and dermal exposure to floodplain soils) for typical and reasonable maximum
exposures.
Exposure Through Fish Consumption
An unknown number of anglers and their families may be consuming fish
from the Sheboygan River and Harbor. Although some anglers may fish for
recreation, others may rely on fish from the AOC to supplement their diet. In
particular, the southeastern Asian community of Hmong may constitute a subsistence
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group of anglers. Approximately 2100 Southeast Asians (about 400 families) live in
the city of Sheboygan (Xa Xov Newsletter, 1991). The Hmong make up a significant
minority population in Sheboygan; there are about 100 families in the local Hmong
Association. Approximately 15% of this population may consume fish as much as
three times a week, although the amount of fish consumed from local sources is
unknown (J. Amrhein, Wisconsin DNR, personal communication, 1992). The Hmong
prefer to fish at Lake Winnebago, the largest inland lake in Wisconsin, because they
can catch species of fish (e.g., white bass) that are similar to those in their original
homeland. However, an unknown number of Hmong may fish out of the Sheboygan
River. The Hmong are not familiar with identifying Wisconsin fish and may be
consuming the more-contaminated, benthic species like carp. Consequently, the
Wisconsin DNR has developed a public education program to inform the Hmong
about fish advisories and to provide visual graphics identifying common fish species.
A workshop has been held in Sheboygan to teach the Hmong where the fish are safe
to eat and how to prepare the fish to reduce the contaminant burden.
As part of the monitoring program for Superfund, fish collection activities are
being carried out by Blasland and Bouck Engineers for Tecumseh Products Co. Four
species of fish were collected from the Sheboygan River during 1991. The fish were
measured, weighed, and analyzed for total PCBs and lipid content; no other
contaminants were analyzed in the fish. Table 2 contains the mean PCB
concentrations, standard deviations (SD), and number of fish analyzed for each of the
sites where river steelhead, chinook salmon, smallmouth bass, and river carp were
collected. The PCB concentrations for river steelhead were based on fillets, whereas
the other fish were analyzed as whole fish. Since PCBs preferentially accumulate in
the fat of fish, the removal of fat during filleting will result in a lower concentration
of PCBs in the fish relative to whole fish. Control spikes and matrix spikes were run
with each set of samples. Little QA/QC information was supplied with the data
sheets containing the analytical results. Nevertheless, the data were determined to be
of adequate quality for use in this risk assessment because the collection and analysis
of data had to conform to Superfund QA/QC protocols.
Of the four species of fish collected from the Sheboygan River, carp were the
most contaminated with PCBs (Table 2). Carp are a good indicator of contamination
problems because they are primarily benthic feeders and generally reside in a local
area. In addition, carp may readily accumulate contaminants in their lipids through
the ingestion and assimilation of contaminated food and possibly through the
consumption of sediment while feeding. Unlike the carp, river steelhead and chinook
salmon are migratory fish that spend most of the year in Lake Michigan; these fish
are no longer stocked in the river, and the migrations of salmon and trout back to the
Sheboygan River have almost ended (B. Eleder, USEPA Region V, personal
communication, 1992). Smallmouth bass may also travel within the Sheboygan River
and between the river and nearshore Lake Michigan area; as seen in Table 2, these
fish accumulated a greater burden of PCBs than the steelhead and salmon.
The equation used to estimate intake of PCBs due to the ingestion of
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TABLE 2. MEAN PCB CONCENTRATIONS IN FOUR SPECIES OF FISH
COLLECTED FROM THE SHEBOYGAN RIVER
Mean
PCB Cone. SD
Fish/Location/Collection Date (mg/kg) (mg/kg) N
River Steelhead
From 22nd St. to Esslinger Park
(4-11-91 and 4-25-91) 0.97 0.44 11
Chinook Salmon
Strawberry Creek (10-16-91) 2.97 1.0 42
Kiwanis Park (9-18-91) 3.2 1.1 40
Lower Harbor (9-18-91) 2.93 1.1 41
Smallmouth Bass
Kiwanis Park (7-16-91) 3.7 1.1 9
Rochester Park (7-16-91) 9.7 4.5 8
Between Kohler Dams (7-17-91) 8.14 3.6 8
River Carp
Kiwanis Park (7-16-91) 12.1 5.6 25
Rochester Park (7-16-91) 48.9 39.2 25
Between Kohler Dams (7-17-91) 41.9 16.7 24
contaminated fish is provided in Table 3. The parameter values used to estimate
intakes are given in Table 4 for typical, reasonable maximum, and subsistence
exposures. Parameter values were obtained from recommended EPA sources and
published studies, whenever possible. In some cases, professional judgment was
used to make conservative estimates. For instance, the fraction of fish assumed to be
ingested from the Sheboygan River AOC was estimated due to a lack of information
for this exposure parameter.
Exposure Through Dermal Contact with Floodplain Soils
Dermal exposure to contaminated floodplain soils may occur at Esslinger and
Kiwanis Parks in the city of Sheboygan. People may be exposed to soils while
playing softball at Kiwanis Park or while playing in any of the parks' areas where the
soil has been exposed. The soil samples used in this exposure assessment were
collected in the upper 7.5 cm of the soil profile and composited before analysis; the
soil samples collected from both parks were overlain with grass cover. The exposure
assessment for this pathway is probably very conservative because most of the soils
in both parks appear to be covered by grass and other vegetation.
The equation used to estimate intakes of PCBs is given in Table 5 and the
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TABLE 3. EQUATION USED TO ESTIMATE CONTAMINANT INTAKES DUE
TO INGESTION OF FISH
Intake =
C X IR X FI X EF X ED
BW X AT
where:
Intake
C
ER
FI
EF
ED
BW
AT
Intake Rate (mg/kg-day)
Contaminant Concentration in Fish (mg/kg)
Ingestion Rate (kg/day)
Fraction Ingested from Contaminated Source (unitless)
Exposure Frequency (days/yr)
Exposure Duration (yr)
Body Weight (kg)
Averaging Time (days)
exposure parameters used in that equation are given in Table 6. This exposure
pathway assumed that an individual wore a long sleeve shirt, pants, and shoes under
a typical exposure scenario; thus, the exposed skin surface was limited to the head
and hands (USEPA, 1989b). Under the reasonable maximum exposure scenario, an
individual would wear a short sleeve shirt, shorts, and shoes; thus, the head, hands,
forearms, and lower legs would be exposed (USEPA, 1989b). The surface area of the
exposed skin was estimated by age group values given in the EPA's "Exposure
Factors Handbook" (USEPA, 1989b). Children and teenagers were assumed to have
dermal contact with the soils 5 days/week during June through August and 2
days/week during May and September (i.e., 83 days). Adults were assumed to have
contact with the soils 2 days/week during June through August (i.e., 26 days). For
the dermal adherence of soil, a range of values from 0.2 to 1.5 mg/cm2 appear
possible; a conservative central value of 1.0 mg/cm2-event was used (USEPA, 1989a).
The absorption of PCBs through the skin was assumed to be 6% (C. Braverman,
USEPA Region V, personal communication, 1992). The exposure assessment was
divided into three age groups: 2-6, 7-17, and 18-70 years. These age groups were
selected because children are at an increased risk to dermal exposure to contaminants
due to their greater surface-to-volume ratio. In addition, children are more likely
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TABLE 4. PARAMETERS USED IN ESTIMATING CONTAMINANT INTAKES
DUE TO INGESTION OF FISH FROM THE SHEBOYGAN RIVER
Var.
IR
n
EF
ED
BW
AT:
Units
kg/day
-
day/yr
yrs
kg
days
Value
Used
0.0192
0.054
0.13
0.05
0.1
0.2
350
9
30
70
25550
Reference
Typical: West et al. (1989)
Reasonable Maximum Exposure (RME): USEPA
(1991a)
Subsistence fishing: used the 95th percentile daily
intakes averaged over 3 days for consumers of fin fish
[Pao et al. (1982) cited in USEPA (1989a)]
Typical: study assumption
Reasonable Maximum Exposure: study assumption
Subsistence fishing: study assumption
USEPA (1991)
Typical: USEPA (1989a)
Reasonable Maximum and Subsistence Exposures:
USEPA (1989a)
50th percentile average for adult men and women
(USEPA, 1989b)
70 yrs x 365 days/yr
than adults to spend time playing outdoors. The typical exposure duration of 9 years
and reasonable maximum exposure duration of 30 years during a 70-year lifetime
were subdivided among the age groups (Table 6). Thus, the proportion of the age
group exposure duration (X) divided by the entire exposure duration (i.e., 9 years for
typical and 30 years for reasonable maximum exposures) was equivalent to the ratio
of the age group range divided by 70 years. For example, the proportion of a typical
9 year exposure (i.ev X) that the 7-17 year old age group would experience would be
calculated as follows:
X years = 11 years
9 years 70 years
X = 1.4 years
8
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TABLE 5. EQUATION USED IN ESTIMATING THE ABSORBED DOSE OF PCBS
DUE TO DERMAL CONTACT WITH FLOODPLAIN SOILS
j X SA± X AF X ABS X EFd X ED± X CF
X ATi
where:
AD
CS
AF
ABS
EF;
ED,
CF
Absorbed Dose (mg/kg/day)
Age Group
Chemical
Chemical Concentration in Soil (mg/kg)
Age Group Specific Skin Surface Area Available for Contact (m2)
Soil to Skin Adherence Factor (mg/cm2)
Absorption Factor (unitless)
Age Group Specific Exposure Frequency (events/yr)
Age Group Specific Exposure Duration (yr)
Conversion Factor (10"6 kg/mg)
Age Group Specific Body Weight (kg)
Age Group and Pathway Specific Period of Exposure, Averaging Time (days)
RISK ASSESSMENT
Carcinogenic risks were estimated as the incremental probability of an
individual developing cancer over a lifetime as a result of exposure to PCBs. The
risk was computed by multiplying the exposure intake by the oral slope factor for
PCBs (i.e., 7.7 (mg/kg-day)"1). Since slope factors based on dermal exposure have not
been derived, the oral slope factor was used. The resulting carcinogenic risk estimate
for both exposure pathways would generally represent an upper-bound estimate; this
is because slope factors are usually based on upper 95th percentile confidence limits.
The EPA believes it is prudent public health policy to consider actions to mitigate or
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TABLE 6. PARAMETER VALUES USED IN ESTIMATING THE ABSORBED DOSE
DUE TO DERMAL CONTACT WITH FLOODPLAIN SOIL (NUMBERS
IN PARENTHESES CORRESPOND TO REASONABLE MAXIMUM
EXPOSURES)
Var.
AF
ABS
CF
SA,
EF(
BW,
AT
ED,
Units
mg/cm2
~
kg/mg
cm2
/event
events
/yr
kg
days
years
Age Class
(years)
-
-
2-6
7-17
18-70
2-6
7-17
18-70
2-6
7-17
18-70
2-6
7-17
18-70
Value Used
1.0
0.06
10"6
1400
(2500)
2000
(5100)
2020
(5200)
83
83
26
17
44
70
25550
0.64
(2.1)
1.4
(4.7)
6.8
(22.7)
Reference
Study Assumption
Recommended Value (C.
Braverman, Region V, personal
communication, 1992)
USEPA (1989b)
USEPA (1989b)
USEPA (1989b)
USEPA (1989b)
USEPA (1989W
USEPA (1989b)
Study Assumption
Study Assumption
Study Assumption
USEPA (1989b)
USEPA (1989b)
USEPA (1989b)
70 yrs x 365 days/yr
Proportion of 9 yr exposure
Proportion of 30 yr exposure
Proportion of 9 yr exposure
Proportion of 30 yr exposure
Proportion of 9 yr exposure
Proportion of 30 yr exposure
10
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minimize exposures to contaminants when estimated, upper-bound excess lifetime
cancer risks exceed the 10~5 to 10"6 range, and when noncarcinogenic health risks are
estimated to be significant (USEPA, 1988).
The carcinogenic risk from consuming either river steelhead, chinook salmon,
smallmouth bass, or river carp was greater than 1 person in 100,000 contracting
cancer during their lifetime for all exposure scenarios (Tables 7-9). The risk was
about an order of magnitude less for the migratory species of river steelhead and
chinook salmon than for smallmouth bass and river carp. As would be expected for
a bottom feeding fish, carp accumulated the greatest PCB burden and resulted in the
worst carcinogenic risk. The risk was slightly greater at Rochester Park and in
between the Kohler Dams than at Kiwanis Park for carp and smallmouth bass. The
cancer risk increased by at least an order of magnitude with each greater exposure
scenario. The subsistence exposure scenario was of particular concern, especially for
people who consumed carp.
The estimated carcinogenic risk due to dermal exposure to contaminated
floodplain soils was on the order of 10~7 under typical exposures for all age groups
(Table 10). The risk increased by about an order of magnitude for reasonable
maximum exposures (Table 11). Under this latter exposure scenario, the carcinogenic
risk was at a borderline level of concern.
The carcinogenic risk from consuming contaminated fish was several orders of
magnitude greater than the lifetime risk of dermal exposure to floodplain soils. Thus,
the additive risks for both exposure scenarios is essentially the same as the fish
consumption risk.
The risk estimates derived for both exposure pathways may have been
overestimated because the only available oral slope factor for PCBs was based on
Aroclor 1260. Aroclor 1260 is not representative of the kinds of PCBs found in the
Sheboygan River AOC. The primary Aroclor mixture used in the Sheboygan River
area consisted of Aroclors 1248 and 1254; the most prominent congeners in this
mixture have been detected in fish from the river (David, 1990). Since Aroclor 1260
contains more highly chlorinated congeners (as well as potentially toxic coplanar
congeners) than Aroclors 1248 and 1254, these risk estimates may be overly
conservative.
UNCERTAINTIES
People in the vicinity of Sheboygan, WI, may be at an increased risk of
developing cancer during their lifetime if they consume fish from the Sheboygan
River and Harbor. However, a number of assumptions and estimated values were
used to develop this prediction. Most risk estimates derived from environmental
data contain a large amount of uncertainty (i.e., on the range of at least an order of
magnitude or greater) (USEPA, 1989a). This section will qualitatively identify the
11
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TABLE 7. CARCINOGENIC RISK FROM CONSUMING SHEBOYGAN RIVER
FISH, TYPICAL EXPOSURE, FI = 0.05
Mean Carcinogenic
PCB Cone. Intake Lifetime
Fish/Location/Collection Date (mg/kg) (mg/kg-day) Cancer Risk
River Steelhead
From 22nd St. to Esslinger Park
(4-11-91 and 4-25-91) 0.97 1.64E-06 1.3E-05
Chinook Salmon
Strawberry Creek (10-16-91) 2.97 5.02E-06 3.9E-05
Kiwanis Park (9-18-91) 3.2 5.41E-06 4.2E-05
Lower Harbor (9-18-91) 2.93 4.95E-06 3.8E-05
Smallmouth Bass
Kiwanis Park (7-16-91) 3.7 6.26E-06 4.8E-05
Rochester Park (7-16-91) 9.7 1.64E-05 1.3E-04
Between Kohler Dams (7-17-91) 8.14 1.38E-05 1.1E-04
River Carp
Kiwanis Park (7-16-91) 12.1 2.05E-05 1.6E-04
Rochester Park (7-16-91) 48.9 8.27E-05 6.4E-04
Between Kohler Dams (7-17-91) 41.9 7.08E-05 5.5E-04
site-related variables and assumptions that may contribute the greatest amount of
uncertainty to the risk estimates. These uncertainties include the following
assumptions and estimates:
• A complete QA/QC review of the fish and floodplain soil data sheets
could not be made because of a lack of information supplied with the
data sheets. However, since the data had to comply with Superfund
QA/QC requirements, it was deemed acceptable for use in this risk
update. The uncertainty associated with using this data is probably
low.
• Contaminant burdens in fish may decrease depending on how the
fish is prepared and cooked. In addition, the use of whole fish data
for chinook salmon, smallrnouth bass, and river carp may be overly
conservative. Contaminant levels may be reduced 10-70% depending
on how the fish is prepared and cooked (H. Humphrey, Michigan
Department of Public Health, personal communication, 1989). Because
of this wide range, the uncertainty associated with the resulting
overestimation of risk is not well established.
12
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TABLE 8. CARCINOGENIC RISK FROM CONSUMING SHEBOYGAN RIVER
FISH, REASONABLE MAXIMUM EXPOSURE, FI = 0.1
Fish/Location/Collection Date
Mean
PCB Cone.
(mg/kg)
Carcinogenic
Intake
(mg/kg-day)
Lifetime
Cancer Risk
River Steelhead
From 22nd St. to Esslinger Park
(4-11-91 and 4-25-91)
Chinook Salmon
Strawberry Creek (10-16-91)
Kiwanis Park (9-18-91)
Lower Harbor (9-18-91)
Smallmouth Bass
Kiwanis Park (7-16-91)
Rochester Park (7-16-91)
Between Kohler Dams (7-17-91)
River Carp
Kiwanis Park (7-16-91)
Rochester Park (7-16-91)
Between Kohler Dams (7-17-91)
0.97
2.97
3.2
2.93
3.7
9.7
8.14
12.1
48.9
41.9
3.08E-05
9.42E-05
1.01E-04
9.29E-05
1.17E-04
3.08E-04
2.58E-04
3.84E-04
1.55E-03
1.33E-03
2.4E-04
7.2E-04
7.8E-04
7.2E-04
9.0E-04
2.4E-03
2.0E-03
3.0E-03
1.2E-02
l.OE-02
The assumptions made about exposure frequency and duration
variables, body weight, life expectancy, and population characteristics
were appropriate. Many of these assumptions (e.g., body weight, life
expectancy, exposure frequency) were based on EPA guidance (USEPA,
1989a,b; 1991) and probably have a low to moderate level of uncertainty
associated with them. Professional judgment was used to determine the
fraction of fish ingested from the Sheboygan River, and a moderate level
of uncertainty was probably associated with this assumption.
The use of an oral slope factor for PCBs was appropriate for the
dermal exposure pathway. Since, a dermal slope factor was not
available, the oral slope factor represented a "best estimate." A
moderate amount of uncertainty is probably associated with this
assumption.
The assumption of 6% dermal absorption of PCBs was appropriate.
Major uncertainties exist concerning the extent to which a chemical is
percutaneously absorbed and in the extent to which a chemical will
partition from soil to skin. In addition, percutaneous absorption of a
chemical in a soil matrix may depend on characteristics of the soil, such
as particle size and organic carbon content. The EPA is considering
13
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TABLE 9. CARCINOGENIC RISK FROM CONSUMING SHEBOYGAN RIVER
FISH, SUBSISTENCE EXPOSURE, FI = 0.2
Fish/Location/Collection Date
Mean
PCB Cone.
(mg/kg)
Carcinogenic
Intake
(mg/kg-day)
Lifetime
Cancer Risk
River Steelhead
From 22nd St. to Esslinger Park
(4-11-91 and 4-25-91)
Chinook Salmon
Strawberry Creek (10-16-91)
Kiwanis Park (9-18-91)
Lower Harbor (9-18-91)
Smallmouth Bass
Kiwanis Park (7-16-91)
Rochester Park (7-16-91)
Between Kohler Dams (7-17-91)
River Carp
Kiwanis Park (7-16-91)
Rochester Park (7-16-91)
Between Kohler Dams (7-17-91)
0.97
2.97
3.2
2.93
3.7
9.7
8.14
12.1
48.9
41.9
1.50E-04
4.60E-04
4.96E-04
4.54E-04
5.73E-04
1.50E-03
126E-03
1.88E-03
7.58E-03
6.49E-03
1.2E-03
3.5E-03
3.8E-03
3.5E-03
4.4E-03
1.2E-02
9.7E-03
1.4E-02
5.8E-02
5.0E-02
using an absorption factor of 6% as a default value for PCBs; this value
may change as additional data from laboratory studies becomes
available. A moderate level of uncertainty is probably associated with
this exposure parameter.
Current levels of exposure will remain constant over the duration time
of the exposure (i.e., 9 or 30 years). A moderate to high level of
uncertainty is probably associated with this assumption. Due to the
remediation efforts in the Sheboygan River, the contaminant
concentrations in fish would be expected to decrease with time.
Concentrations of PCBs in floodplain soils may also be altered with time
through processes such as microbial degradation. In addition, the
consumption of fish from the river could increase if fish are restocked in
the Sheboygan River. The Wisconsin DNR released clipped steelhead
trout in the Sheboygan River during the fall of 1990 to help assess
cleanup plans for the river and harbor (Wisconsin DNR, 1990). The
marked steelhead were stocked at 7.5 to 9 on in size and were predicted
to move out into Lake Michigan during the spring or summer of 1991.
The study will be used to determine whether PCBs taken up by the
young fish during this time contribute significantly to total PCB
concentrations in returning adults.
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• Neglecting other chemicals, besides PCBs, may not be conservative.
No other chemicals, besides PCBs, were analyzed in the fish. Since
PCBs are the primary organic contaminant in the Sheboygan River, the
carcinogenic risk may be appropriate as calculated. Information on
metals and other pesticides would have been necessary to estimate
noncarcinogenic risks.
Overall, a moderate level of uncertainty appears to be associated with the
carcinogenic risk estimates for people who consume fish from the Sheboygan River
and have dermal contact with contaminated floodplain soils. These risk estimates
will be most useful as a benchmark to compare against future risk estimates. In
particular, the baseline carcinogenic risks presented in this report can be compared to
the estimated risks resulting from different remediation scenarios.
CONCLUSIONS
The results of this baseline human health risk assessment indicate that fish
consumption should be avoided from the Sheboygan River AOC. In addition, dermal
exposure to floodplain soils appears to be of marginal concern under the reasonable
maximum exposure scenario. The results of this risk assessment are not directly
comparable to the human health endangerment assessment given in the RI/ES report
because different exposure parameters were often used. However, some
generalizations can be made between the two risk assessments.
• PCBs accounted for most (or all) of the carcinogenic risk.
• Concentrations of PCBs in fish tissue collected from the Sheboygan
River have decreased over the past 10 years. Although the carcinogenic
risk for the typical exposure scenario has decreased by one to two
orders of magnitude compared to the RI/FS endangerment assessment,
the estimated risk levels still warrant a fish advisory for the AOC.
• The RI/ES report indicated that the noncarcinogenic risk from either
consuming fish or dermally exposing the feet to river bank soils was not
significant. Likewise, if heavy metals had been measured in the fish
and soil samples used in this risk assessment, the noncarcinogenic risks
would probably have been below a level of concern.
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TABLE 10. ESTIMATED CARCINOGENIC RISK DUE TO DERMAL EXPOSURE TO CONTAMINATED
FLOODPLAESf SOILS, TYPICAL EXPOSURE SCENARIO
PCB Age Group (years)
Cone.
Site (mg/kg) 2-6 7-17 18-70 Lifetime
Esslinger Park 2.1 1.7E-07 2.0E-07 1.9E-07 6E-07
KiwanisPark 1.5 1.2E-07 1.4E-07 1.4E-07 4E-07
TABLE 11. ESTIMATED CARCINOGENIC RISK DUE TO DERMAL EXPOSURE TO CONTAMINATED
FLOODPLAIN SOILS, REASONABLE MAXIMUM EXPOSURE SCENARIO
PCB Age Group (years)
Cone.
Site (mg/kg) 2-6 7-17 18-70 Lifetime
Esslinger Park 2.1 9.7E-07 1.7E-06 1.7E-06 4E-06
KiwanisPark 1.5 7.0E-07 1.2E-06 1.2E-06 3E-06
16
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REFERENCES
Blasland and Bouck Engineers. 1990. Remedial Investigation/Enhanced Screening
Report Sheboygan River and Harbor. Final Report for Foley &
Lardner/Tecumseh Products Company.
David, M.M. 1990. PCB Congener Distribution in Sediment, Fish and Water. M.S.
thesis. University of Wisconsin-Madison.
Eleder, B.L. 1991. Sheboygan River and Harbor, Sheboygan, Wisconsin. In:
Biological Remediation of Contaminated Sediments, with Special Emphasis on
the Great Lakes, C.T. Jafvert and J.E. Rogers (eds.). pp. 50-54
U.S. EPA. 1988. Risk Management Recommendations for Dioxin Contamination at
Midland, Michigan. Second Edition. U.S. Environmental Protection Agency,
Chicago, IL. EPA-905/4-88-005.
U.S. EPA. 1989a. Risk Assessment Guidance for Superfund: Human Health
Evaluation Manual Part A. Interim Final. OSWER Directive 9285.7-Ola.
U.S. EPA. 1989b. Exposure Factors Handbook. U.S. Environmental Protection
Agency, Washington, DC. EPA/600/8-89/043.
U.S. EPA. 1991. Risk Assessment Guidance for Superfund. Volume I: Human
Health Evaluation Manual. Supplemental Guidance: "Standard Default
Exposure Factors." Interim Final (March 25,1991). OSWER Directive 9285.6-
03.
Wisconsin DNR. 1990. Information Bulletin (December 6, 1990). Department of
Natural Resources, Southeast District Headquarters, Milwaukee, WI.
Xa Xov Newsletter. 1991. Hmong Mutual Assistance Association of Sheboygan, Inc.
10:3.
17
*O.S. GOVERNMENT PRINTING OFFICE 1993-747-248
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